The purpose of this research is to investigate various behavioral, pharmacological, neurochemical and immunological means whereby the self- administration of opiates and psychomotor stimulant drugs can be suppressed or extinguished. Rhesus monkeys will be conditioned to lever press for intravenously administered drug reinforcement. The effects of punishment of drug responding by electric shock or the loss of other reinforcers will be investigated. A series of amphetamine derivatives will be investigated to determine the structural characteistics necessary for the drug to serve as a positive reinforcer. The final experiments concern the "blocking" of the pharmacological actions of these drugs which account for their positive reinforcing actions. This will be accomplished through: pretreatment with pharmacological antagonists; depletion of neurohumoral mediators responsible for reinforcement; production of antibodies to amphetamines and opiates through active immunization. In addition to suggesting various treatment procedures, this research will contribute to an understanding of the basic behavioral and biological mechanisms underlying drugs as reinforcers.